Ricoh CX6 has a 10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Smooth Imaging Engine IV processor. On the other hand, Olympus TG-4 has a 16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features TruePic VII processor.
Olympus TG-4's sensor provides 6MP more than Ricoh CX6's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the CX6 and TG-4 sensor size comparison.
Ricoh CX6 and Olympus TG-4 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Ricoh CX6 has 59% larger pixel area compared to Olympus TG-4, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.